@writerscookie -No, leave this alone too UNLESS there is a very clear relationship between this class and your intended major ... a connection that doesn't appear elsewhere in your application.
For instance, if you've applied as an engineering major but there's no sign of any interest or experience in engineering in any of your other course listings or EC's and this is a ROBOTICS class, then it's worth telling the college in an email now.
@CometCatcher -If you are applying to colleges that require a transcript from your high school (meaning most but not all colleges), then definitely let this go. But if your self-reported classes are on the ONLY list of classes that a college will see, then send a brief emailed correction. If you've sent a transcript, do nothing. It's not any sort of problem.
@hellebore--That part of the Common App is confusing, and tons of teenagers make the same --or a similar--mistake. The college folks are used to it, and so your daughter doesn't need to send a correction. The colleges will use the official score, so don't worry about this at all.
@AimingTop50 -No big deal. Leave it alone. Of course, if you happen to be in an interview situation or you find you have to email any of your colleges for more important reasons, then it's fine to say, "Oh, by the way, I guess I wasn't very 'honorable' when I mistakenly added a year to my NHS involvement on my application!" ;-) But, trust me, no one will notice this tiny mistake, and it will be far more noticeable--and annoying--if you were to send a correction.